The present invention relates to an image generating apparatus or image processor such as a color printer. More particularly, the invention relates to a means for adjusting the color balance of the image to be printed.
As an apparatus to which the present invention is applicable, there is used an image generating unit (image processing unit) which generates visual color image, such as a laser printer utilizing an electrophotographic technique, a thermal printer or an ink jet printer. Such an image generating unit is used for example as a copying apparatus.
When a colored original is to be copied by the copying apparatus, a user sometimes wishes to change the color balance of the copy as he or she likes, irrespective of that the apparatus is adjusted to print the copy as the original color or not, or in case that the original is too reddish, for example.
In an analogue type color printer such as the electrophotographic color printer, the color balance is adjusted by changing the bias voltage of the development for each of color elements yellow (Y), magenta (M) and cyan (C).
On the other hand, in a digital type color printer, the color balance can be digitally adjusted since the original is digitally processed after being read by a sensor.
In either type of color printer, when three colors, that is red (R), green (G) and blue (B), are considered, red (R), for example, is weakened either by reducing the red color element or by strengthening green (G) and blue (B). However, in either case, the color tone of the entire print is changed. Therefore, the user has to go through several times of trial and error each time changing the color balance of the copy so as to get a copy colored as desired, which is very troublesome and inefficient.